Chemical Engineering Archives

7581. The overall mass transfer co-efficient for the absorption of SO₂ in air with dilute NaOH solution can be increased substantially by

Increasing the gas film co-efficient

Increasing the liquid film co-efficient

Increasing the total pressure

Decreasing the total pressure

✅ The correct answer is option A.

7582. Advantage of continuous drying over batch drying is that the

Drying cost per unit weight of dried product is less

Product with more uniform moisture content is produced

Equipment size required is smaller

All of the above

✅ The correct answer is option D.

7583. The most economical range of absorption factor is

0 to 0.5

0 to 3

1.25 to 2

5 to 15

✅ The correct answer is option C.

7584. Coffee is prepared from coffee beans by leaching with

Cold water

Hot water

Dilute hot caustic solution

Naphtha

✅ The correct answer is option B.

7585. Which of the following equipments is not used in liquid-liquid extraction?

Pachuka tank

Agitated vessels

Centrifugal extractors

Packed towers

✅ The correct answer is option A.

7586. Co-current absorbers are usually used when the gas to be dissolved in the liquid is

Sparingly soluble

Highly soluble

A pure substance

A mixture

✅ The correct answer is option C.

7587. Dew point of a gas-vapour mixture

Increases with temperature rise

Decreases with temperature rise

Decreases with decrease in pressure

Increases with increase in pressure

✅ The correct answer is option C.

7588. Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ coloumn.

Spray

Packed

Bubble cap plate

Wetted wall

✅ The correct answer is option D.

7589. In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer.

The entire amount of C is transferred to solvent B

Less than 2 kg but more than 1 kg of C is transferred to solvent B

Less than 1 kg of C is transferred to B

No amount of C is tranferred to B

✅ The correct answer is option A.

7590. The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is

0.5

150

✅ The correct answer is option A.